Automatic switch



Nov. 8, 1932.v H. L.. VAN VALKENBURG 1,886,508

AUTOMATIC SWITCH Filed May 14, 1951 2 Sheets-Sheet gwoento'c Nov. 8, 1932. i H. l.. VAN VALKENBURG 1,886,608

AUTOMATIC SWITCH Filed May 14, 1951 2 Sheets-Sheet 2 wif gva/vento@ I 5W/ Mw@ m f/wmdm Patented Nov. 8, 1932 Umrao STATES PATENT: OFFICE HERMON Il. VAN VALKENBURG, 0F WAUWATOSA, WISCONSIN, ASSIGNOB TO SQUARE D COMPANY, OF DETROIT, MICHIGAN AUTOMATIC SWITCH Application led. May 14,

This invention relates to automatic. switches.

Objects of this invention are to provide an automatic electric switc which is responsive to pressure variations and electrical overload conditions, which will respond to either condition an indefinite number of times, which may be reset when the -overload condition is removed.

Further objects are to provide an automatic electric switch for controlling a motor or other device operating a pump so that a predetermined pressure may be automatically maintained, the switch opening and closing in accordance with changes in pressure without requiring any attention on the part of an operator', but which will automatically operate the same switch to hold the motor circuit open when an electrical overload occurs until the device is reset afterthe overload condition has been corrected, thereby providing in one and the same device an automatic control, constantly functioning r under normal condition to cut the motor into and out of circuit, and also automatically functioning to cutthe motor out of circuit when an electrical overload occurs, and hold the circuit open irrespective of the pressure responsive means until the device is reset by the attendant.

Further objects are to provide a compact device which, although having the characteristics enumerated above, is lnevertheless simple in construction, free from delicate or easily damaged parts, and which is easy to install, and which is eminently practical in actual operation.

An embodiment of the invention is shown in the accompanying drawings, in whichz- Figure 1 is a plan view of the device with the cover of the casing removed.

Figure 2 is a sectional view on the line 2-2 of Figure 1.

Figure 3 is a sectional view on the line 3 -3 of Figure 1.

y Figure 4 is an enlarged sectional view on the line 4-f4 of Figure 3.

Figure 5 is a perspective view of the pawl of the electrical overload device.

which is automatic in its action, and' 1931. Serial No. 537,250.

Figure Gis a perspective view of the guide for the pawl shown in Figure 5.

Referring to the drawings, it will be seen flexible diaphragm 3. It is preferableto provide a fitting 4 communicating /vvith the space below the diaphragm and rigidly supporting the diaphragm casing and consequently the entire structure, so as to facilitate the simple mounting of the device. A pressure-plate or pressure head 5 bears against the upper side of the diaphragm and carries three rigidly attached upwardly projecting plungers 6 which pass through the upper portion of the diaphragm casing 2 and into the housing 1. The upper ends of these posts or vplungers 6 are reduced and pass through positioning washers 7 and into a lower plate 8 which supports the lower end of the main spring 9.

The spring plate 8 is provided with a plurality of upturned lugs 10 which aid in retaining the lower end of the spring in correct position,.and is also provided with a pair of downwardly extending lugs 11. A. main bell crank rock lever 12 the casing, as indicated at 12', and has its shorter arms pivoted to the lugs 11, as indicated at 13, see Figure 2.

A central post or stem 14 is rigidly attached to the upper portion of the diaphragm casing and is provided witha threaded upper end upon @which the adjusting nut 15 is carried, such nut serving to adjust the compression of the main spring 9, a suitable washer being preferably positioned beneath the nut 15, as shown in Figure 2.

- The main lever 12 is provided with a pivotally mounted link 16, which is urged dow-nwardly by means of an adjustable spring 17. The spring 17 is preferably attached at its lower end to the main lever 12, and its upper end is attached to a threaded screw 18 provided with a nut 19 equipped with fulcrum is pivotally supported by such rock lever.

A rock plate 22 is pivoted to the casing and provided with a pin 23 which fits within the slotted end of the rock lever 21. The plate 22 is connected' by means of a link 24 with 'a rocking member or lever 25. The link 24 has a slot and pin connection with the lever 25, to

` permit the lever 25 to be rocked to 4the right by overload means hereinafter described. This rocking member or lever is in reality switch operating means and carries a plurality of insulating plungers 26 adjacent its upper end, which are adapted to strike the switch hereinafter described, and open such switch when the switch operating means 25 is rocked in a clock-wise direction, as viewed in Figure 2.

The switch may comprise an insulating block 27 which carries a pair of switch units. Each switch unit consists of a pair of stationary contacts 28 connected, as shown in Figure 2, with the terminal members 29. A floating movable contact member 30 is loosely guided within a cavity 31 formed in the body portion 27, and is preferably provided with contacts adjacent its ends adapted to engage Ithe contacts 28 whenthe switch is closed.

This movable contact element or switch member is biased towards closed position by means y of a spring 32 socketed within the insulating body portion 27.

Any number of these switch members may be provided, two having been shown in the drawings, and each switch unit is separated from the other switch unit by the insulating body 27, preferably additional barriers 33,

see Figure 1, being formed on opposite sides and between the switch members. When the switch is opened, the switch oper-- ating means or lever 25 is rocked in a clockwise direction, as viewed in Figure 2, and the insulating plungers 26 engage the movable contact members 30 directly in line with the springs 32 and force the contact members 30 to the right, as viewed in Figure 2, thus opening the switch. This opening motion is, of course, a snap action, as will be understood from the mechanism previously described'.

The switch operating member or lever 25 is provided with anvupwardly projecting arm 34, which carries a laterally projecting pin 35, see particularly Figure 1. The pin 35 loosely projects through an arcuate slot 36, see Figure 3, formed in a division wall 37 of the main casing 1.

It is to'be distinctly understood that the pressure responsive means for actuating the switch is intended in the broadest aspect of this invention` to show one form of fluid condition responsive means.

This invention provides means responsive to electrical overload which also operates the same switch that is operated by the fluid-condition responsive means. This electric overload device may comprise a plurality of selfsoldering overload devices, such as those described in the copending application of Ivan Corcoran, Serial Number 484,694, release mechanism, filed September |26, 1930. These self-soldering devices each comprise a ratchet `wheel 36, see Figures 3 and 4, which is equipped with a shaft 39 projecting into a metal block 38, solder being provided between the shaft 39 and the metal block and being adapted to melt under overload conditions to thereby allow the ratchet wheel 36 to be freely turned by means hereinafter described. The metal block 38 is clamped to a heating unit 37 carried by terminal posts 40, see particularly Figure 4. The terminal posts 40 connect with the terminal members 41, see Figure 3, to which the leads from the motor extend. It is to be noted that two of these self-soldering overload responsive means have been disclosed in the particular device chosen for illustrating this invention so that these two overload devices mayA beI placed in two of the leads of a three-phase motor for instance, so that if any phase becomes overloaded, one or the other of the overload responsive means will operate. Obviously other circuit connections could be used provided the current flowing through the heating unit corresponded to, or in other words was proportionate to, the load carried by the motor.

The ratchet wheel 36, the block 38 and the heating unit 37 are of well known construction, and it is not believedthat a fuller description is needed.

The construction of these overload self-soldering devices is identical and a description of one will therefore suffice. A pawl 42, see

Figure 4, is provided with an outturned lip 43 adapted to engage and lock against one of the teeth of the ratchet wheel 36. This pawl is loosely and slidably carried by means of a simple guide 44, see particularly Figures 4, 5 and 6. The pawl may consist of a somewhat channel-shaped member provided with a tongue 44 located on the upper side of the guide 44, and with the main body portion 42 located on the under side of the guide 44, the connecting portion 45 being freely slidable within the slot 46 formed in the guide 44.

It is also preferable to indent the connecting forward lip or arm of -formed in the arms 50 of the guides 44. slide may have a reset handle or projecting A portion 51 48, see Figures 1, 4 and 5, attached to the rear lip 49 of the pawl and to the upstanding 'the guide 44, see Figures 4 and 5. The spring 48 thus serves not only to rock the pawl, but'also to urge the pawl towards the right, as viewed in Figure 1.

It will be seen from reference to Figures 1 and 3 that a slide lpreferably of insulating material is loosely guided within slots 52 This extending outwardly beyond the casing and adapted for manual operation to reset the device. The slide 51 is held within theslots 52 by means of a bracket 53, see

Figures `1 and 3.

The slide 51 is provided with a laterally projecting arm 54, see Figures 1 and 3, which carries a plate 55 positioned in the path of movement of the pin 35 so that when the slide 51 moves to the right, 4as viewed in` Figures land 3, the projecting plate 55 will engage the pin 35 and rock the switch operating member or lever 25 in a clock-wise direction thereby opening 'the switch.

The construction is such that either one of the overload devices is adapted to actuate the slide 51. This is accomplished by providing the slide with a 'pair of shoulders 56 and 57 adapted to Vbe engaged by the upstanding rear portion 49 of either one ofthe pawls, as shown in Figure 1. Thus when either pawl is released and is moved to the right, as viewed in Figure 1, by the softening of the solder restraining the corresponding ratchet wheel 36, the slide 51 will be moved to the right and will thus open the switch.

The A switch remains. in open position when one of the overload devices operates until the device is reset by the operator by pressing the Vhandle or projecting portion 51, see Figure 1, inwardly. The self-soldering overload devices, of course, may operate any number ofv times for when the overload is removed, they are again in operative condition. However, after overload, it is necessary tomanually reset the device before the switch can close.

. On the other hand, the fluid condition responsive means may operate any number of times to automatically open or close the switch in accordance with the condition of the fluid. Thus there is an automatic control provided for an. electric motor or similar device,which vis responsive to changes in the fluid condition,

such as changes in pressure for instance,'and which operates intermittently and as often as required without any attention on the part of the operator, and in addition to this. au-

tomatic overload means is provided Awhichv opens `the switch under-,overload conditions and retains the Switchin open condition until reset by the operator. Both these 'devices operate upon the same switch and a unitary andcompact mechanism is therebysecured.

Further the device is simple, it may be cheaply constructed, and it may be easily installed.

Although this invention has been described in considerable detail, it is to be understood that suchdescription is intended as illustrative rather than limiting, as the invention may be variously embodiedand is to be interpreted as claimed. 1

I claim: f

1.A control device comprising fluid condition responsive means; an electric switch normally operated by said iuid condition responsive means; and a plurality of electrical overload devices, each acting independently, for holding said switch open-upon the occurrence of an electrical overload; and manual means for resetting said overload devices.

2. A control device comprisingI an electric switch biased towards closed position, movable means for opening said switch, pressure able means for opening said switch, pressure responsive means, link mechanism including a slotted link and a cooperating pin for nor-` mally operatively connecting said movable means and said pressure responsive means to open said switch when said pressure responsive means moves in one direction, an -electrical overload device for moving said pin within said slot to open said switch when an electrical overload occurs, said electrical overload responsive device holding said pin out of operative connection with said slotted link after overload, a casing surrounding said switch/and said pressurev responsive means, and means accessible externally of said casing for resetting said electrical overload device.

4. A control device comprising an electric switch biased towards closed position, movable means for opening said switch, said movable means having a projectingi pin, pressure l responsive means, link mechanism including aslotted link receiving said pin and cooper- HERMoN L. VAN VALKENBURG. 

